An animal model of pulmonary hypersensitivity to small airborne industrial chemicals is being developed in this laboratory using guinea pigs. Repeated exposure of animals to antigen aerosols, composed of small chemicals (haptens) covalently linked to proteins, resulted in pulmonary sensitivity to the haptenic portions of the antigens. Haptenspecific respiratory sensitivity was accompanied by hapten-specific antibody production, including IgE. To improve simulation of exposure conditions which exist in industry, the above procedure was successfully adapted to permit sensitization of animals to vapors of tolyl isocyanate. Proposed research will be directed toward inhalation sensitization of guinea pigs to numerous small industrial chemicals, and dose-response threshold concentration studies of sensitization. Calibration of the animal model to man will permit prediction of safe exposure levels for industrial workers. Studies to effect desensitization of guinea pigs previously made sensitive to industrial chemicals are planned. Such procedures will employ administration by aerosol or injection of conjugates composed of allergens bound to D-amino acid polymers. The immunologic nature of experimental respiratory sensitivity induced by inhalation of industrial chemicals will be characterized. Periodic evaluation of sera and lung lavage for specific antibodies and/or cells will be performed using PCA and antigen binding techniques. Antigens found to be effective in detecting anti-hapten antibodies in the animal system will be applied to the industrial situation to evaluate sera from workers for analogous anti-hapten antibodies.